(1) Constancy of protein zone positions with focusing time on immobilized pH gradient gels in the pH-range 4-10 was demonstrated. (2) The procedure of focusing with Immobiline containing gels was streamlined by elimination of gel washing and drying to the original weight and pre-electrophoresis. Gradient formation was facilitated by pumping or mechanical 2- syringe device. (3) Pore limit electrophoresis (PLE) in polyacrylamide gradient up to 60% T was developed to serve as a 2nd dimensional size fractionation at the steady state, providing stationary coordinate pairs for spots on a 2-D gel pattern. (4) Agarose gel fiber properties (fiber radius, length per unit weight and volume) were estimated by computer simulation, using polystyrene microspheres as commercially available size standards. The extended Ogston theory was adapted for that purpose by substitution of functions for the fiber and particle properties previously considered constants. Effective gel fiber properties were shown to be a function of gel concentration and of the size of the particle passing through the gel. (5) Agarose gel electrophoretic analysis of plant viruses and polystyrene microbeads was carried out in a discontinuous (moving boundary electrophoresis) buffer system, with stacking gels operative at pH 6.5 and resolving gels operative at either pH 6.5 or 7.2, 0.03 M ionic strength, 0.01 M CHAPS, O degrees C. This has the advantage of allowing for particle separation from dilute samples, and of providing uniformly concentrated starting zones for enhanced resolution. (6) Polyacrylamide gel electrophoresis on 30% Bis-crosslinked gels was applied to polystyrene particles with radii 10 - 60 nm in an attempt to obtain Ferguson plots with simplified curve shape compared to that in agarose, and thus to facilitate the physical characterization of particles. (7) Curvature of Ferguson plots on polyacrylamide gel was determined as a function of crosslinking in order to increase the accuracy of the characteristic free mobility (net charge) values of particles.